diff --git a/build.js b/build.js
index 758fe82..f8bab3f 100644
--- a/build.js
+++ b/build.js
@@ -18,6 +18,15 @@ const removeDirs = (base, filterFn) => {
 	}
 };
 
+const deleteFiles = (basePath, filenames) => {
+	filenames.forEach(filename => {
+		const filePath = path.join(basePath, filename);
+		if (fs.existsSync(filePath)) {
+			fs.unlinkSync(filePath);
+		}
+	});
+};
+
 try {
 	console.log(' Building Moonfin for webOS...\n');
 
@@ -43,6 +52,50 @@ try {
 	const localeDir = path.join('dist', 'node_modules', 'ilib', 'locale');
 	removeDirs(localeDir, (name) => !name.startsWith('en'));
 
+	// Root-level files: phone, currency, unit, address, astronomy data
+	console.log('\n Removing unused ilib data files...');
+	const nonEngLocalefiles = ([
+		'currency.json',
+		'numplan.json',
+		'emergency.json',
+		'unitfmt.json',
+		'phoneloc.json',
+		'phonefmt.json',
+		'iddarea.json',
+		'idd.json',
+		'mnc.json',
+		'address.json',
+		'addressres.json',
+		'astro.json',
+		'pseudomap.json',
+		'collation.json',
+		'countries.json',
+		'nativecountries.json',
+		'ctrynames.json',
+		'ctryreverse.json',
+		'name.json',
+		'lang2charset.json',
+		'ccc.json'
+	]);
+	deleteFiles(path.join('dist', 'node_modules', 'ilib', 'locale'), nonEngLocalefiles);
+
+	// Remove Deseret script locale (historic/obsolete)
+	fs.rmSync(path.join('dist', 'node_modules', 'ilib', 'locale', 'en', 'Dsrt'), {recursive: true, force: true});
+	
+	// Strip bulky files from en/ regional subdirs (keep only sysres, dateformats, list, localeinfo, plurals)
+	console.log('\n Removing non-essential files from en/ regional locale dirs...');
+	deleteFiles(path.join('dist', 'node_modules', 'ilib', 'locale', 'en'), nonEngLocalefiles);
+
+	// Remove unused font weights to reduce size
+	console.log('\n Removing unused font weights...');
+	const fontFiles = ([
+		'MuseoSans-Thin.ttf',
+		'MuseoSans-BlackItalic.ttf',
+		'MuseoSans-BoldItalic.ttf',
+		'MuseoSans-MediumItalic.ttf'
+	]);
+	deleteFiles(path.join('dist', 'node_modules', '@enact', 'sandstone', 'fonts', 'MuseoSans'), fontFiles);
+
 	// Package into IPK
 	console.log('\n Creating IPK package...');
 	fs.mkdirSync('build', {recursive: true});